Porcelain crown.



'L. E. I EVSLIN. PORCELAIN CROWN.

- APPLICATION FILED MAY 14. I903.

UNITED @FFIWE.

LEO E. EVSLIN, OF PEORIA, ILLINOIS, ASSIG-NOR, IBY IVIESNE AESIGNMENTS, '10 DORA. STAILBERG, O1? FHILADELIPHIA, PENNSYLVANIA.

POR ELAIN CROWN.

Application filed May 14:, 1908.

To all whom it may concern:

Be it known that I, Lee E. EvsLIN, a subject of the Emperor of Russia, residing at Peoria, in the county of Peoria and State of Illinois, have invented certain new and useful Improvements in Porcelain Crowns; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

This invention has reference to artificial teeth construction and relates particularly to a new and improved interchangeable crown.

The principal object of my invention is to produce a dental crown having a construction such as to provide a firm means of support therefor, to facilitate fitting and attachment thereof and to dispense with the use of metal on the labial and lingual sides thereof.

Further objects and aims of the invention will more fully appear from the following description, together with the attached drawings, forming a part thereof, in which Figure 1 is a side view of a central incisor as the same would appear, embodying my improvements, and without the backing therefor;

Fig. 2 shows a longitudinal section of the incisor shown in Fig. 1, with the addition of the metallic-tongue, metallic lining therefor, and the metallic backing; the backing and tongue also shown soldered together;

Fig. 3 is a cross section of the incisor, as

the same would appear if taken on the line YY of Fig. 2;

Fig. 4 is a longitudinal sectional view of the incisor, as the same would appear if taken on the line X-X of Fig. 2;

Fig. 5 is a side view of a bicuspid as the same would appear, embodying my improvements and without the backing therefor;

Fig. 6 shows a longitudinal section of the bicuspid shown in Fig. 1, with the addition of the metallic tongue, metallic lining therefor, and the metallic backing; the backing and tongue also shown soldered together;

Fig. 7 shows in elevation and partly in section a crown with my improvements embodied and attached to a root, as the same would appear in actual use, and

Fig. 8 is a view, illustrating how a dummy Specification of Letters Patent.

is preferably oval in shape.

Patented Apr. 30, 191%.

Serial No. 432,941.

would be attached to an abutment with the abutment supported on a root in the manner illustrated in Fig. 7.

Like numerals of reference indicate cor responding parts throughout the figures.

While I have chosen central incisors and bicuspids wherein m improvements are embodied, I have done so merely for the purpose of illustrating the application of the invention to at least two of the different styles of crowns, but it is to be understood that the invention is applicable to all the various styles of crowns and that of course the details of construction as hereinafter referred to in connection with the crowns shown will necessarily have to conform to the various shapes of the other and different forms of crowns to which the invention may be applied.

The porcelain crown is only of the usual form and construction as far as the labial and lingual surfaces are concerned; this will be true whether the crown is an incisor, bicuspid or other form of crown, except as is hereinafter pointed out.

Referring particularly to Figs. 1, 2, 3 and 1, which show a central incisor, the crown itself is indicated as 1, having the labial and lingual surfaces 2 and 3, the biting edge 4 and the lower end surface 5 which surface is known as the cervical border or base. This cervical border, as best seen in Figs. 1, 2 and 41 is somewhat concaved; so that not much bulkiness of porcelain is to be encountered by the dentist while grinding and adjusting this end of the crown which is ground toward the root or the protecting plate of the natural root.

The lingual, or posterior surface 3 of the crown is considerably shorter than the labial surface and is formed with a shoulder or seat 6, which shoulder or seat continuing toward the center of the crown, as best seen in Figs. 1 and 2, makes up the concavity of the lateral sides begun at the labial side of the crown. Extending upwardly into the crown, from the center thereof at the cervical border, is a cavity or socket 7 which The opening of this cavity or socketat the cervical border is enlarged to form a seat 8 adjacent the outer end of the cavity or socket. (See Fig. 2). This seat 8 is rounded-like or cupshaped and diminishes in size and takes a definite oval shape as it merges into the oval shape of the socket produce this result.

In the direction of the longer diameter of the socket the walls thereof communicating with the exterior surface of the cervical border are interrupted by the formation of the seat 8, but in the direction of the shorter diameter of the socket the walls thereof merging into the outer surface of the cervical border are uninterrupted and extend di rectly from the outer end of the socket latorally to the opposite sides of the crown in the same manner as if the portions of the seat 8 were not present in the direction of the longer diameter of the socket. By this means a firmer grip and closer fit may be obtained for the backing. The longer diameter of the ellipse forming this oval cavity or socket, is from the labial surface toward the lingual or posterior surface, as shown in Fig. 8, while the smallest diameter of said ellipse, is from side to side of the crown, also best seen in Fig. 3, and although substantially the entire depth or length of this cavity or socket 7 is of a definite oval shape. The said cavity or socket is tapered toward the biting edge of the crown and takes the shape of the posterior or lingual surface of the crown, as far as the six anterior crowns are concerned, as very plainly seen in Fig. 2, while in the bicuspids, see Fig. 6, or melars, (not shown) the cavity or socket may have substantially the same oval shape with the cup shaped opening, such as shown in Fig. 2, but owing to the bicuspids and molars being bulky, or much wider than the anterior teeth, said cavity or socket may extend directly up into the crown and said cavity or socket may be made much greater in diameter if it is'so desired, although this is immaterial.

Since the socket 7 opens centrally through the concavity of theinner end or cervical border of the crown this concavity may be referred to as an annular seat surrounding the open end of the socket, irrespective of the seat 8.

A metal boxing 9, which is preferably of the same shape or of the same outline as the cavity or socket 7, and seat 8, in both anterior, as well as the posterior teeth, is baked in the crown, while the C1O\ n is in a plastic state in the mold. The porcelain may shape itself nicely all around the metal boxing, particularly at the masticating or biting surfaces of the crown, and also at the cervical border, said boxing at the masticating or biting edge being beveled, as at 10, to obviate all sharp corners, and

at the cervical border, the boxing is also beveled, as at 11, in this way the porcelain is allowed to shape itself nicely all around the edges of the boxing, without, however, permitting the porcelain to enter or lodge itself in the boxing itself.

12 denotes a metal tongue, the main body portion of which is preferably tapered and of oval shape, to fit nicely in the metal boxing 9, which is also shaped to conform to the cavity or socket 7 in the crown, and that portion of said tongue at the cervical border, is also enlarged and shaped to conform to the enlarged outer portion of the metal boxing 9 within the seat 8, and extending outwardly from said metal tongue at the cervical border, is a lug or projection 13, which is adapted to pass through a metal lmcking, in a manner to be described, for the purpose of securing said metal backing to said tongue.

Commencing at the cervical border, the lateral sides, of the crown which, for con venience, I will designate l-l, are fOrmcd with recesses 15, which may be of any suit able depth, and presentinga concave face, or of any other desirable shape, but which are wider at the cervical border and gradually diminish in width toward the cutting edge of the crown, and in the anterior teeth, particularly so on account of the shape of the said teeth, the said recesses or grooves rcsemble somewhat, a pyramid, the side w alls of the recess following the outline of the labial, as well as the lingual surfaces, but where the teeth are bicuspids or molars, the shape of the recesses or grooves may differ a little on account of said bicuspids and molars being much greater in width than the anterior teeth.

These recesses 15 merge into the scat formed by the concavity of the inner end or cervical border of the crown, and the hacle ing, to be specifically referred to, which fits into the seat formed by the concavity of the cervical border, continues therefrom into the recesses 15.

The metal backing of which reference hasv been made, is indicated as 16, and is proided with a central opening 17, whereby the said backing plate may be placed over the lug or projection 13 of the metal tongue 12, and be burnished and caused to conform to the shape of the cervical border 5 of the crown. This metal backing is also of such shape that it may be bent over on to the lateral sides of the crown and depressed or burnished into the recesses or grooves 15 in the lateral sides of the crown, somewhat in the manner seen in Figs. 3 and 1, but the said backing does not extend over on to the labial or lingual surfaces, but is made to conform to the cervical border, as shown in Fig, 2, and has a part which fits the shoulder 6 formed in said cervical border, as also lll) shown in said Fig. 2. After the tongue 12 has been inserted into'the metal backing of the crown, and the metal boxing shaped to conform to the crown, as just previously described, after having been passed over the lug or extension 13 of the tongue, the crown is removed and this metal backing, together with the tongue, is placed in suitable investment material, and said tongue is soldered to said backing, with solder of any suflicient thickness, covering that portion of the backing which conforms to the cervical border of the crown. After this is done, the crown is replaced on the tongue, and finds itself not only held by the tongue within the metal boxing in the cavity or socket in the crown, but said crown is also supported at its cervical border, as well as its lateral sides, by a backing plate strengthened with solder as shown at 18. In individual crowns, this gives a much stronger attachment for the porcelain crown, and when used in connection with crown and bridge work, it proves to be of great advantage as any number of teeth can be united together by virtue of the backing plates being united on their sides by solder, as I will now explain.

The provision of the concavity in the cervical border provides ample space for re taining the solder 18 and provides a suitable surface for the backing to grip. The provision of the recesses 15, continuing from the concavity of the cervical border provides appropriate space for receiving the lateral extensions of the backing without adding bulk to the finished tooth. These recesses also provide an appropriate surface for the lateral extensions of the backing to grip upon and, what is from one point of view very essential, they render the lateral extensions of the backing substantially invisible when the crown is in position in the mouth, because said lateral extensions are to a greater or less extent embedded in the recesses and hidden from view by the relatively raised port-ions defining said recesses.

In Fig. 7, an individual crown is shown, with the backing plate 16 in position on the crown and having the backing of solder 18. To attach such a crown to a root, which may be referred to for convenience, as 19, the same is soldered, through the solder 18, to a facing plate 20, which may be attached to or formed integral with a post 21, which is fastened in the root, as shown. When it is desired to attach a dummy, indicated as 22, see Fig. 8, the dummy which is also provided with a metallic lining, a metallic tongue, and a backing plate, is soldered to the abutment, which I will refer to as 23, see Fig. 8, being similar to that construction shown in Fig. 7, by soldering together, at 24, the adjacent portions of the metallic backing burnished inthe recesses 15 in the sides 14 of the crown. This gives a very strong attachment for the crowns and at the same time there is no gold solder nor any metal frame work on the lingual or posterior surfaces of the teeth.

Having thus fully described my invention, what I claim and desire to secure by Letters Patent of the United States, is:-

1. A porcelain crown provided with a socket therein opening out of the cervica border, said socket substantially cup-shaped at its open end and merging into an oval shape and diminishing in size toward its inner end, and the sides of said crown formed with recesses leading from the cervical border to a point removed from the biti'ng edge of said crown, substantially for the purposes set forth.

2. In teeth construction, a crown having a central socket and its side walls formed with recesses commencing at the cervical border, a metallic tongue for said socket, and a metallie backing fitted to the cervical border of the crown and the recesses in its sides, whereby a pair or more of crowns may have those portions of the backing fitting the recesses in their sides soldered together.

3. A porcelain crown provided with a socket therein opening out of the cervical border, said socket substantially cup shape at its open end and merging into an oval shape and diminishing in s1ze toward its 'inner end, the sides of said crown being formed with recesses leading from the cervical border to a point removed from the biting edge of said crown, in combination with a backing shaped to conform to the cervical border of the crown and having portions burnished in the recesses in the sides of the crown.

4:. An artificial tooth crown having a tapered pin receiving hole extending from its base toward its incisal edge, the lingual wall of the crown at the base thereof being provided with a curved seat upon the outer edge for the reception of an ofi'-set portion on the base of the backing for the tooth crown.

5. An artificial tooth crown having a tapered pin receiving hole extending from its base toward its incisal edge, and a seat at the mouth of the pin receiving hole, the base of the tooth crown being concave, the bottom of the concavity extending to the mouth of the hole for dividing the seat to furnish an uninterrupted wall between the mouth of the hole and the side walls of the tooth crown, the lingual wall at the base of the crown being provided with a curved seat for the reception of the offset portion on the base of the backing for the tooth crown.

6. A backing for an artificial tooth crown comprismg a base and a pin, the said base having a curved shoulder along its back portion only adapted to enter a curved seat in the outer edge of the lingual wall of the tooth crown at the base thereof.

7. An artificial tooth crown having a tongue receiving socket opening through the inner end of thereof, a seat at the mouth of said socket and relatively raised portions at the sides of the crown forming recesses in said sides communicating With said seat for the purpose set forth.

8. An artificial tooth crown having a tongue receiving socket opening through the inner end thereof a seat at the mouth of said socket, and said crown having a recess in the side surface thereof communicating with said seat for the purpose set forth.

In testimony whereof I afiix my signature, in presence of two Witnesses.

LEO E. EVSLIN. \Vitncsses:

CHAS. W. LA lon'rn, LAURA E. CLAYrooL.

60510:: of this patent maybe: obtained for five cents each, by addressing the Commissioner of Patente,

Washington, D. G. 

